DEAR JOAN: A group of three or four Northern mockingbirds is keeping us up at night. They have a distinctive three-part song that includes a part that sounds like a dentist’s drill.

During the day we are OK with it, but the nights have become impossible. The trill drill wakes us up even after taking sleep medicine and wearing ear plugs.

Can you offer suggestions to how these sleepless folks on the mid-Peninsula can encourage the birds to move elsewhere?

B.K.

Palo Alto

DEAR B.: If it helps any, and I’m sure it won’t, yours is not the first or only letter I’ve gotten recently on those darn mockers and their infernal singing. I’m afraid it’s the season for it, and there is very little you can do to make the birds leave.

Mockingbirds are protected by the federal Migratory Bird Act, which makes it illegal to disturb nesting birds, destroy their nests or the eggs. That means the worst you can do to them is shake your fist in their direction. The “fix” must come from you.

But let’s talk first about the birds because they are amazing and while it won’t help you sleep, maybe you’ll have a slightly better opinion of them. Mockingbirds sing for two reasons — to attract a mate and to defend territory. The mating songs occur in the spring, mostly, and generally during the day. While the female can sing, too, she usually is quiet during mating season, listening to her suitors. She puts great store in a male that can sing the most diverse songs, so it’s in his best interest to have an impressive repertoire.

Mockingbirds can imitate 36 species, and many fill out their song books by mimicking other sounds including, unfortunately for the light sleeper, car alarms, cellphone tones and, apparently, dentist drills. A really good songster can perform up to 200 sounds.

The night singing usually is put down to a lonely bachelor still trying to find a mate and getting a little desperate, but that’s not the entire story. A male who has found a mate and become a proud daddy will also sing at night to protect his territory from avian encroachers. He will sing tirelessly in an effort to convince would-be intruders that the area already is overrun with birds.

It’s a good trick and, I wager to say, he has managed to fool you into thinking there are three or four mockingbirds in your backyard. Most likely, it is just one very dedicated bird.

Deterrents such as scarecrows, plastic owls and the recorded bird calls of other birds won’t do much to warn the mockingbird off a territory he has already staked and has a vested interest in defending.

You would be better off to invest in double-pane windows — they will cut down on your PG&E bill, too — and some white noise machines. Running a fan at night will help, or playing a relaxation CD with sounds of the surf or a water fall, can help drown out the racket.

The good news is the singing will eventually stop when the babies fledge. The bad news is it will eventually start up again.

Mistaken identity

The good folks at the St. Francis Animal Protection Society in Campbell are suffering from a case of mistaken identity. Some folks are confusing them with the St. Francis All Creature Rescue and Sanctuary, which is under investigation as a “rescue for profit.”

The names are similar, but there is no connection between the two. The Animal Protection Society has a long and outstanding reputation as a friend to animals, and is worthy of your support.

Joan Morris is the pets & wildlife columnist for the Bay Area News Group. She also writes about gardening and is the founder of Our Garden, a demonstration garden in Walnut Creek. Morris started her career in 1978 as a reporter for a small New Mexico newspaper. She has lived in the Bay Area since 1988.

He’s no snowman and he certainly doesn’t have a corncob pipe and a button nose, but Humane Society Silicon Valley’s eponymous white pooch is a jolly, happy soul who loves to play and fares better outdoors than indoors.